Plug in your computer, plug in your headphones or IEMs, whatever they are, and go! That's the Woo Audio WA7 fireflies for you.
For my written review, see my review: A Tale of Two Tube Amps
The glass does get quite warm. But since it's a thick bit of sturdy stuff, it's no real worry.
Nice review Amos! That is certainly a nice looking unit, the glass top really lifts the overall design. Do the tubes make the glass very hot?